104 DR. ST. G. MivART ON [Mar. 18, 



I think it well to note these characters as indicating, with respect to 

 the tail, what is possibly another local variety of C. azarcB, but I 

 submit that the characters are by no means sufficient to justify its 

 acceptation as a distinct species on the evidence of a single skin un- 

 accompanied by its skull. I am the more inclined to regard it as a 

 mere variety because the skin of C. azartB brought by Fitzroy from 

 Patagonia (No. 227 a) shows two imperfect annulations towards the 

 root of the tail. 



(.5) Canis entrerianus is a species instituted by Burmeister (* Reise 

 durch La Plata,' 1861, p. 400) for a Canine form found by him 

 between the rivers Parana and Uruguay. He obtained specimens 

 exemplifying very different ages of both sexes. He describes it as 

 reddish-yellow brown, the hairs of the back having black terminations 

 and being whiter further down ; face and limbs red-brown like the 

 back ; front of the neck, breast, and inner side of the limbs whitish 

 or pale yellowish red ; end of the tail black. 



The young (which he found sucking in January) were of a yellow- 

 ish brown, except the face, limbs, and tail-end, which were blackish 

 brown. 



The mother, which was in milk on the 27th October, was reddish 

 brown but dappled by the intermixture of white and black bristly 

 hairs. The front of the neck, breast, and inner side of the limbs 

 were reddish yellow. 



An old male was a much lighter and clearer yellow colour, without 

 any dappling on the back, being of a homogeneous tint, the bristly 

 hairs having less black and no white. Underparts white. 



The male was taken on 27th February', so that he had probably a 

 summer dress on, while the female was in winter clothing, which 

 was longer and thicker than the male's. She had sis mammae. 



The skulls of the male and female differed considerably, that 

 of the female being more contracted behind the orbits. The length 

 of the fourth upper premolar was in the male 15 and the two molars 

 20 ; in the female P^ was 14 and M.1+-M.2 15 ; the mean of the 

 two being as 100 to 120. The difference between the male and the 

 female is so remarkable that it would almost justify a little scepticism 

 as to the numbers given. 



The external characters I have quoted — characters which differ 

 so much according to sex or season — do not seem to me enough to 

 distinguish and establish a species, although they are very interesting 

 as pointing out another local variety — that of Entre Rios — of the 

 very widely diffused C. azarce. 



(6) Canis gracilis. — This is again a species proposed by Bur- 

 meister ('Reise durch La Plata,' ISfil, p. 406, and 'Description 

 phys. Rep. Argentine,' vol. iii. p. 150) for a Dog inhabiting the 

 bushy pampas of the environs of Mendoza. There he often saw it 

 alive, and many skins brought to market. Amongst these was one 

 with the dorsum and end of the tail rusty red. He describes the 

 species, however, as an uncommonly slender form, more elegant than 

 his C. griseus. The ground-colour is pale yellowish grey on the back — 



